Steps
1. Preheat the oven to 375°F.
2. In a bowl, mix together mayonnaise, mustard, and diced onions.
3. In a baking dish, layer the sliced potatoes, shredded turkey, and the mayonnaise mixture.
4. Cover with foil and bake for 30 minutes.
5. Remove foil and bake for an additional 15 minutes until potatoes are tender and the top is golden brown.